Thermochemistry of Sodium Tungstate, Silver Tungstate and Tungstic Acid

The heat of solution of Na2WO4 has been measured and the standard heat of solution calculated to be -1.6 kcal/mole. Because this heat of solution is very differnent from that calculated from previously reported heats of formation, Robert L. Graham and Loren G Hepler have measured the heat of reaction of crystalline tungstic acid(H2WO4) with excess aqueous sodium hydroxide and have found the standard heat of solution of AgNO3 in water have been measured and the standard heats found to be -12.39,-8.12 and 5.42 kcal/mole, respectively. The heats of reaction and solution have been used to calculate the heats of formation of WO4-(aq), Na2WO4(c) and Ag2WO4(c) to be -266.6,-379.6 and -230.7 kcal/mole, respectively. The thermodynamics of solution of Ag2WO4 is discussed in terms of polytungstate formation.


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Why Professional Dart Choose Tungsten?

Having a high density is quite important to darts, because the high-density dart have a steady center, so it’s necessary to processing it with high precision. Tungsten is a metal of high density, so it became the best material for a high-quality dart.

Why tungsten dart takes the most percentage of the professional dart, the main reasons are following:
Size is the first reason. With the same weight, the diameter of the brass dart is twice as much as the tungsten dart. To hitting the bull’s-eye easily, we need a small but heavy dart, so tungsten dart is the best choice for a professional dart game.

Secondly, dart barrel is tungsten dart’s main part, which is made of high proportion of tungsten alloy. It takes the advantage of heavy, small, anti-corrosion, antioxidant, recycled.

Thirdly, tungsten darts have the delicate carve patterns, so gorgeous and stunning. It can be use for sport and collection. With the popularize of darts sport, more and more people became a big fan of tungsten dart.

If you want a delicate and high-quality dart, you can contact us online, our information is at the bottom of the article. Thank you so much for your attention!

 

tangsten dart

 

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Tungsten Contact Materials Selection

For a given application requirements, you must choose a proper tungsten contact material to make the function of the device get as greater possibility of success in the design process as possible. Besides, adjusting the final properties of addictives, materials particle size and furnace temperatures of the chosen tungsten contact materials are available. And the cost of tungsten contact is cost-effective.

Tungsten contact, generally, its thermal and electrical conductivity will increase and contact wear erosion resistance will decrease as the tungsten content of conductive metal increases, however, contact wear erosion resistance and contact welding becomes a significant concern. On the contrary, contact wear erosion resistance will increase as the refractory metal content increases; what’s more, there is less possibility of tungsten contact welding.

In a word, the selection of tungsten contact materials should take its wear erosion resistance and other properties, and its cost into account.

 

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The Selection of Tungsten Point Materials

You should select appropriate tungsten point material to realize the function of the device in the design process for a given application requirements. The subsequent process is also very important, for example, the control of the materials particle size, the ratio of addictives, appropriate furnace temperatures control. And the cost of tungsten point is cost-effective.

In general, the increase of tungsten point’s thermal and electrical conductivity and the decrease of tungsten point’s wear erosion resistance are as the increase of conductive metal content. However, the weld of tungsten point and its wear erosion resistance become a crucial concern. On the contrary, as the increase of the refractory metal content, tungsten point’s wear erosion resistance will increase. Furthermore, the tungsten point welding is less likely.

All in all, the function and cost of the tungsten contact materials should be considered in the selecting process.

 

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Tungsten Point Materials and Applications

Tungsten point‘s materials and applications

Tungsten point materials

Applications

Tungsten point

It can be employed in relays, magneto breaker, alarms, automatic switches, etc.

Tungsten-silver-nickel point

It could be used as an important part in command switches, AC / DC relays, washing machine timers, contactor, light control switches, thermostat and so on.

Silver tungsten point

It could be used as a part in circuit breakers, heavy AC / DC contactors and so on.

Silver tungsten carbide point

It can be applied in high current load switching equipment.

Tungsten-silver graphite point

It is usually used for protecting the switches, which is paired with silver-nickel.

Tungsten-silver metal oxide point

It has a wide application in large capacity relays, leakage protection switches, contactors, small and medium capacity and low voltage circuit breakers, the power protection switches and so on.

 

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